You're roughly describing 6to4, where 2002:c0a8:0809::123 belongs to 192.168.8.9. Though 6to4 is mostly deprecated, and you generally don't use it with "private

You're roughly describing 6to4, where 2002:c0a8:0809::123 belongs to 192.168.8.9. Though 6to4 is mostly deprecated, and you generally don't use it with "private" IPv4 addresses, unless you're incrementally deploying IPv6 in an environment where half the switching fabrics are IPv4-only and the other half can do hardware-encap/decap 6to4 but not 6rd.